Interesting note: We replaced our inefficient 1990’s Vulcan gas heater (which used $90/month of gas) eight months ago with a modern Rinnai Infinity – but for the first 4-5 months it kept using $70-80/month which seemed high. Now it has settled around $55/month on average as expected (see below from Sept 2018 for justification / payback period). I wonder if new gas heaters have a ‘settling in’ period where they are less efficient for a few months? Strange.

April 2019 – Autumn – $260.75

Energy Online (Electricity) – $179.39 (711 units)

(Guests staying, heat pump cranking – winter is here)

Energy Online (Gas) – $81.36

March 2019 – Autumn – $138.93

Energy Online (Electricity) – $84.98 (316 units)

Energy Online (Gas) – $53.95

February 2019 – Summer – $121.27

Energy Online (Electricity) – $76.07 (277 units)

Energy Online (Gas) – $45.20

January 2019 – Summer – $283.66

Energy Online (Electricity) – $211.41 (843 units)

So I made a big boo-boo during January. While cooking tea for the kids I left the bath running and flooded our house (both floors). Soaking the carpets and flooring. We had commercial dryers & dehumidifiers running for a whole week (at 9kW peak load!). Hence the expensive power bill 🙁

Thankfully as I write the house is dry and we have new carpet down. So everything is back to normal… finally.

Energy Online (Gas) – $72.25

December 2018 – Summer – $168.83

Energy Online (Electricity) – $104.08 (390 units)

Energy Online (Gas) – $64.75

November 2018 – Spring – $154.87

Energy Online (Electricity) – $81.66 (302 units)

Energy Online (Gas) – $73.21

October 2018 – Spring – $183.98

Energy Online (Electricity) – $102.64 (389 units)

Energy Online (Gas) – $81.34

Had extended family staying for school holidays, hence the higher gas (hot water) bill.

September 2018 – Spring – $172.47

Energy Online (Electricity) – $101.96 (385 units)

Energy Online (Gas) – $70.51

Major gas upgrade this month. We replaced our 20-year-old Vulcan Freeloader gas water heater with a modern continuous flow water gas water heater (Rinnai Infinity A26, $3050 incl. GST installed).

This will give us more outdoor space (the Freeloader was large and in a silly location) and I am expecting will lower our gas cost per month from $90 to $60-ish on average, which gives a rough payback period of 7 – 9 years.

This means we shouldn’t have to use the underfloor heating very much at all. The underfloor heating works well but is 100% resistive and expensive to run – about 75c per hour – and needs to run for 3-4 hours to start making a difference.

By comparison, the heat pump as has a rated power input of 1.7kW for 7.3kW of heat output and can heat the house easily within 30-45 min. Efficiency.

On average we should save approx $2-3 a day compared to the underfloor (maybe more, because we often forget to turn the underfloor off before going to bed) which gives a rough payback period of around 8-10 years.

Energy Online (Gas) – $91.66

July 2018 – Winter – $285.78

Energy Online (Electricity) – $192.96 (795 units – yikes!!)

A couple of things massively influenced our power bill during July:

1 – We have been keeping the house warm using the existing underfloor heating system (Hotwire 3kW) which is expensive to run.

2 – There is an old spa pool, which I decided to get up and running for fun. It is a nice luxury… but also poorly insulated needing $6 – 7 of power per day to stay hot (more than $2000 per year). So after two weeks, we switched it off again. The spa experiment used about $90 of power over the two weeks.

A little bit larger than our previous place, we now have four bedrooms and two bathrooms, but also less energy efficient. Lighting is a mix of inefficient 1990’s incandescent & halogen lighting which I have already started replacing with new LED downlights. Not much in the way of heating or cooling – but we are looking to put a heat pump in soon.

On the gas side of things, we have moved from a modern continuous flow gas water heater to a 21-year-old Vulcan Freeloader 300. The Vulcan looks like it’s a combination gas water heater and water storage cylinder. My gut feeling is that the Vulcan is going to use a lot more gas than our usual $55/month – but time will tell.

Because of the move, $ this month are likely to be a little messed up – as they will cover two properties for the last week of May. Should settle down by the June billing cycle.

April 2018 – Autumn – $145.18

Flick Electric Co. (Electricity) – $85.81 (312 units)

Energy Online (Gas) – $59.37

Heated towel rails kicked in again this month…. but warm towels are worth it. Also had family to stay for a week so some extra power usage inevitable.

March 2018 – Autumn – $111.17

Flick Electric Co. (Electricity) – $64.36 (234 units)

Energy Online (Gas) – $46.81

February 2018 – Summer – $100.60

Flick Electric Co. (Electricity) – $66.32 (237 units)

Energy Online (Gas) – $34.28

January 2018 – Summer – $125.96

Flick Electric Co. (Electricity) – $86.91 (263 units)

Energy Online (Gas) – $39.05

December 2017 – Summer – $121.38

Flick Electric Co. (Electricity) – $63.58 (172 units)

Energy Online (Gas) – $57.80

November 2017 – Spring (feels like summer!) – $144.17

Flick Electric Co. (Electricity) – $84.27 (281 units)

(Interesting that we used approx 20% less power than last month, but our bill was very similar. Stubbornly high spot prices during November – potentially the unseasonably warm weather?)

Energy Online (Gas) – $59.90

October 2017 – Spring – $136.60

Flick Electric Co. (Electricity) – $88.95 (354 units)

Energy Online (Gas) – $47.65

September 2017 – Spring – $178.01

Flick Electric Co. (Electricity) – $125.98 (517 units)

A very wet and cold month meant lots of heat pump and dryer for us. Power consumption 36% above last month but power bill up only 19% due to lower wholesale energy costs. Plenty of hydro lake water to go around I guess!

Energy Online (Gas) – $52.03

August 2017 – Winter – $163.93

Flick Electric Co. (Electricity) – $106.35 (381 units)

Lower power consumption combined with a drop in electricity spot prices compared to June and July has resulted in a significantly lower power bill for August.

Energy Online (Gas) – $57.58

July 2017 – Winter – $233.83

Flick Electric Co. (Electricity) – $181.39 (543 units)

Some pricey power this month. Our most expensive day was Friday 14th July where we used more than $18 of at an average cost of 50c / unit.

We also hit our maximum power consumption for the year, averaging 17 ½ units of power per day, double what we used back at the start of the year. The increased consumption is most likely due to heat pump, towel rail and dryer.

Energy Online (Gas) – $52.44

June 2017 – Winter – $192.01

Flick Electric Co. (Electricity) – $138.88 (453 units)

Our May and June power bills are around 2x the summer months due to:

a) Increased wholesale power pricing (‘spot pricing’) due to falling hydro lake levels. For much of the year, the South Island’s hydro generation is exported to the North Island via the HVDC link. Low lakes = less generation available = higher priced generation (e.g. Huntly) required more often = higher prices.

b) It’s been cold and wet. So we have used more power than usual. Heated towel rails, heat pump in the mornings and dryer after work.

Energy Online (Gas) – $53.18

May 2017 – Autumn – $ 163.80

Flick Electric Co. (Electricity) – $108.22 (412 units)

Energy Online (Gas) – $55.58

April 2017 – Autumn – $93.04

Flick Electric Co. (Electricity) – $65.36 (267 units)

Energy Online (Gas) – $27.68

March 2017 – Autumn – $110.60

Flick Electric Co. (Electricity) – $57.88 (221 units)

Energy Online (Gas) – $52.72

February 2017 – Summer – $123.06

Flick Electric Co. (Electricity) – $61.32 (238 units)

With our recent house move, I have decided to move our power to Flick Electric Co. The business model seems a step in the right direction for the power industry, with our unit cost for power changing in line with the wholesale power market.

We will see how it goes and I hope to provide an update on my Flick experience in a couple of months.

Energy Online (Gas) – $61.74

As Flick does not do gas, I have kept our Energy Online account as the mains gas rates were decent and with no contract, we can always switch later.

January 2017 – Summer – $168.58

Energy Online

December 2016 – Summer – $140.28

Energy Online

November 2016 – Spring – $218.00

Energy Online

October 2016 – Spring – $182.73

Energy Online.

September 2016 – Spring – $251.81

Energy Online

August 2016 – Winter – $204.31

Energy Online

July 2016 – Winter – $343.76

Energy Online

June 2016 – Winter – $285.92

Energy Online

May 2016 – Autumn – $197.18

Energy Online

April 2016 – Autumn – $71.12

Energy Online. Actual reading benefits from over-estimate in March.

March 2016 – Autumn – $250.26

Energy Online. Power consumption was over-estimated, this reverses in April.

February 2016 – Summer – $205.32

Energy Online

January 2016 – Summer – $204.79

Energy Online

=====

Nathan’s Notes:

Our family power bill figures are what we actually paid each month, they include GST and any prompt payment discount.